Regional Δ14C patterns and fossil fuel derived CO2 distribution in the Beijing area using annual plants

Abstract

The level of atmospheric Δ 14 C and the fossil fuel derived CO 2 concentration in the Beijing area from May to September, 2009, were systematically analyzed based on radiocarbon ( 14 C) measurements of annual plants by accelerator mass spectrometry (AMS). The results show that the maximum Δ 14 C in Beijing was 29.6‰±2.2‰, and the minimum was −28.2‰±2.5‰, with a trend of decreasing Δ 14 C from the outer suburbs to inner suburbs to the urban center. This trend correlates well with increases in fossil fuel derived CO 2 caused by human activities such as population density, industrial emissions and traffic, with lower values of atmospheric Δ 14 C associated with more intensive human activities. The fossil fuel derived CO 2 concentrations from May to September, 2009, ranged from 3.9±1.0 ppm to 25.4±1.0 ppm. It was calculated that each additional 1 ppm of CO 2 from fossil fuels depleted the atmospheric Δ 14 C by approximately 2.70‰. This study suggests that 14 C measurements of annual plants by AMS provide an effective method to rapidly trace fossil fuel derived CO 2 .